It is known to make window frames from aluminium or aluminium alloy. To this end, traditionally an outer shell and an inner shell of aluminium or aluminium alloy are connected together by means of a number, mostly two, of thermal barriers.
The thermal barriers primarily have a mechanical function to connect the inner shell and outer shell together and are thus of great structural importance. This means that they must be made of hard rigid plastic.
The outer shell, inner shell and thermal barriers are formed as profiles, whereby a composite profile is formed after these components are connected together.
Such a composite profile is then further processed by a window manufacturer into a window of the desired size, whereby the window manufacturer saws the composite profile to the desired lengths in order to produce the window.
In order to obtain good thermal insulation, open spaces in a window are filled with a thermal insulation as much as possible. This generally includes a foam body or a structured hollow body that is provided with partitions so that relatively small chambers are formed and can greatly reduce the heat transfer between the inside and outside of the window by the convection of air in these spaces.
Such spaces are the space between a glass panel and a frame in which this glass panel is supported on the one hand, and on the other hand the space between a fixed frame and a sash that must be able to move with respect to one another.
These spaces are located next to a thermal barrier and it would also be attractive to be able to integrate a thermal insulation in a thermal barrier, because the thermal insulation is immediately affixed when assembling the composite profile, such that considerable cost benefits can be achieved.
However this is not done for a number of reasons.
Firstly it would lead to problems when fitting glass supports.
Because the thermal barriers do not have sufficient strength, sturdy glass supports have to be provided in a frame in a number of places that form a bridge between the inner shell and outer shell, so that a glass panel is supported on the inner shell and outer shell via the glass support.
If a thermal insulation is now integrated with a thermal barrier, a part of this extended thermal barrier, i.e. the part that corresponds to the part that forms the thermal insulation, must be selectively removed at the places where a glass support has to be placed.
As in such a composite profile there is no, or only very limited, access from the side to the part of the extended thermal barrier that forms the thermal insulation, in practice this is not done, in any case not without the risk of damaging the thermal barrier itself and thereby jeopardising the structural strength of the frame.
Secondly such a part of the extended thermal barrier can be damaged relatively easily during the transport of the composite profiles.
Thirdly such an integration of a thermal insulation with a thermal barrier gives the disadvantage that the flexibility of the use of the composite profiles is limited.
Although not necessary for reasons of heat transfer by means of convection, in some cases it can nevertheless be desirable to provide a rebate gasket that ensures the windproofing and waterproofing of a window instead of, or together with, a body to fill a space.
However, when a thermal insulation is integrated with a thermal barrier the design of the insulation is already fixed during the production of the composite profile such that it can no longer be adjusted, and the flexibility of a window manufacturer to use another insulation is taken away.
In view of the above disadvantages, composite profiles in which a thermal insulation is integrated in an insulating set are not supplied by suppliers of composite profiles.
Instead of this the window manufacturer first places the glass supports in the desired place, then determines the necessary lengths and types of the thermal insulations, makes them to the desired size from longer pieces and affixes them on the composite profiles, generally on the thermal barriers thereof.
As already noted above this requires a lot of work so that the construction of windows is expensive.